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Homework Help: Simple echo question

  1. Mar 6, 2006 #1
    i need help on the following problem:
    "carol drops a stone into a mine shaft 122.5 m deep. How soon after she drops the stone does she hear it hit the bottom of the shaft?"
    i know that the acceleration is 9.8m/s^2 but i can't use it as speed in the speed=distance/time equation
    please help me. thanx
  2. jcsd
  3. Mar 6, 2006 #2
    Break the problem into two parts.

    Calculate t1, the time it takes the stone to fall from her hand to the bottom of the well.

    Then find t2, the time it takes the sound to travel from the bottom of the well to the top.

    The total time is just t1 + t2.
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